Moons Big & Small: Perigee & Apogee Moons

A comparison of the perigee and apogee Moons of 2011.

Moons Big and Small, photo by Kevin

Last night I learned that the full moon was at apogee, and with all the love I’ve given to supermoons, I figured that I should throw a bone to the tiny ones as well. Kevin is a regular on Michigan in Pictures with his stunning photos of the night sky. He made a comparison of the perigee and apogee Moons of 2011 and shared this explanation:

The Full Moon of October 2011 was near apogee, which is the furthest point in the Moon’s orbit of the Earth. Back in March, you may recall, the Moon was at it’s closest point in its orbit to Earth, and the media dubbed it the “Supermoon.”

According to several sources, the difference in size between the March Full Moon and the October Full Moon is 12.3%. Why is there such a difference, you may ask?

Well, the Moon’s orbit around the Earth is elliptical, just as the Earth’s is around the Sun. That means that as the object – the Moon in this case – orbits the “parent” object (the Earth) it will never be the same distance away.

The image I put together shows the difference between the size of the Moon at perigee (March 2011) and apogee (October 2011). This comparison makes the size difference quite clear.

Kevin adds that both images of the Moon were taken with exactly the same equipment. View it bigger and see more in his massive The Moon slideshow.

PS: This full moon is the strawberry moon, and you can click that link for more about that and (unsurprisingly) a photo from Kevin!

Dance of Light, March of Science

Dance of Light, photo by Eric Hackney

“Nothing in life is to be feared, it is only to be understood. Now is the time to understand more, so that we may fear less.”
― Marie Curie

The NOAA/NWS Space Weather Prediction Center (SWPC) has forecast a G2 level storm for tonight, which may very well produce Northern Lights! The SWPC is an invaluable scientific resource that is wholly produced by our tax dollars. In addition to letting us know when northern lights are possible, the SWPC helps to maintain our modern communication grid when the Sun gets a little extra exuberant.

It’s my heartfelt belief that one of the duties of our government is to work to make our country the leader in scientific advancement. As threats in public health, the environment, and a host of other realms increase, we need to be investing much more in science, not less.

To any who are participating in any of the 15 local Science Marches in Michigan today, the March for Science in Washington DC, or anywhere else, I salute you.

View Eric’s photo bigger and see more in his Personal Favorites slideshow.

PS: Happy Earth Day everyone.

22-Degree Radius Halo

22 degrees at Van’s Beach, photo by Andrew McFarlane

Atmospheric Optics is an excellent resource for rainbows and similar phenomena. Their page on 22-degree halos says:

22º radius halos are visible all over the world and throughout the year. Look out for them (eye care!) whenever the sky is wisped or hazed with thin cirrus clouds. These clouds are cold and contain ice crystals in even the hottest climes.

The halo is large. Stretch out the fingers of your hand at arms length. The tips of the thumb and little finger then subtend roughly 20°. Place your thumb over the the sun and the halo will be near the little finger tip. The halo is always the same diameter regardless of its position in the sky. Sometimes only parts of the complete circle are visible.

Much smaller coloured rings around the sun or moon are a corona produced by water droplets rather than ice crystals.

Lots more at Atmospheric Optics!

See the photo bigger and view more on my Instagram.

More rainbows, sundogs, etc. on Michigan in Pictures – seriously cool stuff in here folks!

The science behind the magic: Fall color explained

yellow-glory-by-scottie

Untitled, photo by Scottie

The Science of Color in Autumn Leaves from the United States National Arboretum is such an excellent explanation of the science behind the magic of Michigan’s fall color show that I try and share it every year:

The process that starts the cascade of events that result in fall color is actually a growth process. In late summer or early autumn, the days begin to get shorter, and nights are longer. Like most plants, deciduous trees and shrubs are rather sensitive to length of the dark period each day. When nights reach a threshold value and are long enough, the cells near the juncture of the leaf and the stem divide rapidly, but they do not expand. This abscission layer is a corky layer of cells that slowly begins to block transport of materials such as carbohydrates from the leaf to the branch. It also blocks the flow of minerals from the roots into the leaves. Because the starting time of the whole process is dependent on night length, fall colors appear at about the same time each year in a given location, whether temperatures are cooler or warmer than normal.

During the growing season, chlorophyll is replaced constantly in the leaves. Chlorophyll breaks down with exposure to light in the same way that colored paper fades in sunlight. The leaves must manufacture new chlorophyll to replace chlorophyll that is lost in this way. In autumn, when the connection between the leaf and the rest of the plant begins to be blocked off, the production of chlorophyll slows and then stops. In a relatively short time period, the chlorophyll disappears completely.

This is when autumn colors are revealed. Chlorophyll normally masks the yellow pigments known as xanthophylls and the orange pigments called carotenoids — both then become visible when the green chlorophyll is gone. These colors are present in the leaf throughout the growing season. Red and purple pigments come from anthocyanins. In the fall anthocyanins are manufactured from the sugars that are trapped in the leaf. In most plants anthocyanins are typically not present during the growing season.

As autumn progresses, the cells in the abscission layer become more dry and corky. The connections between cells become weakened, and the leaves break off with time. Many trees and shrubs lose their leaves when they are still very colorful. Some plants retain a great deal of their foliage through much of the winter, but the leaves do not retain their color for long. Like chlorophyll, the other pigments eventually break down in light or when they are frozen. The only pigments that remain are tannins, which are brown.

The explain that because the starting time of the whole process is dependent on night length, fall colors appear at more or less the same time every year and are not overly dependent on temperature, rainfall or other factors, other than the fact that weather can shorten or prolong the show by stripping leaves from trees.

Click through to the US Arboretum for more and also see Fall & Fuit from the Science of Color!

View Scotties’ photo bigger and see more in his Infrared slideshow.

Tons more fall photos on Michigan in Pictures!

Only Getting Hotter

Eye in the Sky by Noah Sorensen

Eye in the Sky, photo by Noah Sorensen

“The heat is rising and only getting hotter, ready to blow
I think I’ll pour myself a glass of water, let it flow
She’ll show you what she’s made of
Yeah she’s comin’ for ya
She’s gonna try to break ya
Yeah she’s comin’ for ya
No, she don’t mess around”
-Cage The Elephant, Mess Around

You know that when I pull out Cage the Elephant lyrics, I’m probably going to say something that will anger a slice of Michigan in Pictures readers, so be warned! Longtime readers will also know that I am pretty committed to saying what I want to say, so it’s probably good keep that in mind as well.

Speaking of warnings, the National Aeronautics and Space Administration (NASA) spends a lot of time looking at the Earth and crunching data from an extensive satellite and – in conjunction with the National Oceanic and Atmospheric Administration (NOAA). Anyway, these folks – literally rocket scientists – have reported (based on science and data) that the Earth is warming at an unprecedented rate:

The planet is warming at a pace not experienced within the past 1,000 years, at least, making it “very unlikely” that the world will stay within a crucial temperature limit agreed by nations just last year, according to Nasa’s top climate scientist.

This year has already seen scorching heat around the world, with the average global temperature peaking at 1.38C above levels experienced in the 19th century, perilously close to the 1.5C limit agreed in the landmark Paris climate accord. July was the warmest month since modern record keeping began in 1880, with each month since October 2015 setting a new high mark for heat.

But Nasa said that records of temperature that go back far further, taken via analysis of ice cores and sediments, suggest that the warming of recent decades is out of step with any period over the past millennium.

“In the last 30 years we’ve really moved into exceptional territory,” Gavin Schmidt, director of Nasa’s Goddard Institute for Space Studies, said. “It’s unprecedented in 1,000 years. There’s no period that has the trend seen in the 20th century in terms of the inclination (of temperatures).”

Read on for more. I’d like to go on record as a parent and member of the human race that I’m really alarmed by this, and also the fact that what appears to be a serious emergency is being ignored.

View Noah’s photo background bigtacular and see more in his slideshow.

I would really like to share the video of Mess Around from Cage the Elephant because I really like the band. In the interests of responsibility however, here’s a 30-second video showing the temperature rise of the last 145 years:

North Bar Lake in Sleeping Bear Dunes

North Bar Lake Sleeping Bear Dunes

North Bar Lake, Sleeping Bear Dunes, photo by jdehmel

The Sleeping Bear Dunes National Lakeshore pages on North Bar Lake and the North Bar Lake Overlook say (in part):

The small lake below is North Bar Lake. The name describes how the lake formed: it is ponded behind a sand bar. At times, the sand bar builds up and separates North Bar Lake from Lake Michigan. At other times, a small connecting channel exists between the two lakes. North Bar Lake occupies part of a former bay on Lake Michigan. This ancient bay was flanked by headlands on both sides: Empire Bluffs on the south and Sleeping Bear Bluffs on the north. Shorelines have a natural tendency to become straighter with time. Wave action focuses on the headlands and wears them back, while shoreline currents carry sediment to the quiet bays and fill them in. Deeper parts of the bay are often left as lakes when sand fills in the shallower parts. The same process that formed North Bar Lake also formed many of the other lakes in northern Michigan: Glen, Crystal, Elk and Torch Lakes, for example.

…North Bar Lake is one of the most popular beaches in the Lakeshore because it has shallow, clear water over a sandy bottom makes for warmer swim than in Lake Michigan. But for those who like the refreshing cool water and wave action of the big lake, you can walk across the low dunes that separate the two lakes in just a couple of minutes. The beaches of pure sand and the small outlet to Lake Michigan is ideal for the kids to play.

View jdehmel’s photo background bigilicious and see more in his Sleeping Bear Dunes slideshow.

More dunes and more summer wallpaper on Michigan in Pictures.

Why is Ice Blue or Green?

The Blue Ice

The Blue Ice, photo by Charles Bonham

The Causes of Color answers the question: What causes the blue color that sometimes appears in snow and ice?

As with water, this color is caused by the absorption of both red and yellow light (leaving light at the blue end of the visible light spectrum). The absorption spectrum of ice is similar to that of water, except that hydrogen bonding causes all peaks to shift to lower energy – making the color greener. This effect is augmented by scattering within snow, which causes the light to travel an indirect path, providing more opportunity for absorption. From the surface, snow and ice present a uniformly white face. This is because almost all of the visible light striking the snow or ice surface is reflected back, without any preference for a single color within the visible spectrum.

The situation is different for light that is not reflected, but penetrates or is transmitted into the snow. As this light travels into the snow or ice, the ice grains scatter a large amount of light. If the light is to travel over any distance it must survive many such scattering events. In other words, it must keep scattering and not be absorbed. We usually see the light coming back from the near surface layers (less than 1 cm) after it has been scattered or bounced off other snow grains only a few times, and it still appears white.

In simplest of terms, think of the ice or snow layer as a filter. If it is only a centimeter thick, all the light makes it through; if it is a meter thick, mostly blue light makes it through. This is similar to the way coffee often appears light when poured, but much darker when it is in a cup.

Click through for lots more about light & color!

Charles took this photo last March off Gills Pier on the Leelanau Peninsula when there was a whole lot more ice than there is this winter. View it background bigilicious and see more in his Leelanau Peninsula slideshow.

More winter wallpaper and more amazing ice on Michigan in Pictures.